At least 90 people were killed in an Israeli strike on the Jabalia refugee camp in northern Gaza as calls for a ceasefire continue to grow.
The United Nations Security Council looked set to vote on a demand that Israel and Hamas allow aid access to the Palestinian enclave.
On Sunday Israel opened the Kerem Shalom crossing between Israel and Gaza opened for aid trucks for the first time since the outbreak of war.
But Israeli authorities said they were determined to fight on to eliminate Hamas, which has run Gaza since 2006 and is sworn to Israel's destruction.
Former British Defence Secretary Ben Wallace warned on Monday that Israel risks losing legal authority for its war in Gaza by going on a crude and indiscriminate “killing rage” against the Palestinian people.
He warned the country’s tactics will “fuel the conflict for another 50 years” and will radicalise young Muslims across the world.
Lord Cameron, the Foreign Secretary, also joined with his German counterpart to call for a “sustainable ceasefire” in the territory, adding that “too many civilians have been killed”.
Separately, another missile attack on a house killed 24 people, Hamas Aqsa radio said. A medic said dozens of people had been killed or wounded in the home and nearby buildings.
“We believe the number of dead people under the rubble is huge but there is no way to remove the rubble and recover them because of the intensity of Israeli fire," he said by telephone on Sunday.
The Israeli government said it operated against militant targets and that it takes extraordinary measures to avoid hitting civilians.
Around 19,000 Palestinians have been killed, according to Gaza health officials, since October 7 when Hamas terrorists killed 1,200 people and captured 240 hostages in their surprise raid.
The Israeli military released the names of four more soldiers who had died in combat in Gaza, bringing to 126 the number of soldiers killed in the strip since Israel launched a ground invasion in late October.
Israel's war on Hamas has razed large parts of Gaza and displaced the majority of its 2.3 million residents, many now living in makeshift shelters without clean water and food and fighting diseases.
Human Rights Watch said on Monday that Israel was using starvation as a weapon by deliberately blocking the delivery of water, food, fuel and razing agricultural areas.
“For over two months, Israel has been depriving Gaza's population of food and water... reflecting an intent to starve civilians as a method of warfare," Omar Shakir, Israel and Palestine director at Human Rights Watch said in a statement.
However, the Kerem Shalom border crossing opening could allow the doubling of the amount of food and medicine reaching Gazans.
The United Nations Security Council could vote as early as Monday on a proposal to demand that Israel and Hamas allow aid access to the Gaza Strip - via land, sea and air routes - and set up UN monitoring of the humanitarian assistance delivered.
Diplomats said the fate of the draft Security Council resolution hinges on final negotiations between Israel ally and council veto power, the United States, and the United Arab Emirates, which has drafted the text.
